1. Field of the Invention
The present invention relates to a developing device for making electrostatic or magnetic latent images visible with toner powder.
2. Description of the Related Art
The developing device is usually intended to supply developer to a photosensitive drum while rotating a developing roller, and make latent images visible with developer thus supplied. In a conventional developing device, a metal blade is usually pressed against the developing roller to charge the developer and thin it to a certain thickness. As disclosed in a Japanese Patent Application H1-124880, there is disclosed a roller type restricting member for restricting the thickness of the developer layer. In this restricting member, a relatively thin developing layer is formed on the developing roller. Thus, a sufficient developing density can not be obtained in respect to a developing process. In the case of the conventional developing device of this kind, stress is likely to be added to the developer. Particularly, when a non-magnetic developer is used, its hardness and its melting point are low. When the metal blade is pressed against the developing roller, therefore, the developer is degraded and melted.